Civilizations have made a variety of ceramic articles such as cooking and serving vessels, water and other fluid containers, tiles, bricks, etc., for thousands of years. These were typically coloured or decorated with metal oxide type pigments that developed colours or more intense colours during an elevated temperature firing of the pigment and ceramic article. The metal oxide type colouration pigments were thought to chemically interact and interpenetrate and develop colours at high temperatures with the ceramic composition and/or with more glassy compositions sometimes applied with the colouration pigments or subsequently applied. The more glassy compositions were often to provide impermeable or barrier properties to the outer surface of the ceramic article (to protect the ceramic article from environmental materials with which it might come in contact).
With conventional organic pigments and the few inorganic pigments (e.g., TiO2, silica, and talc) in polymeric organic binder, the particle size and particle uniformity are very important to achieve consistent and intense colouration. Inorganic mixed metal oxide pigments used in inorganic ceramic colouration are generally not as well understood as organic pigments. The particle size of the inorganic metal oxide pigments generally has not been studied and controlled to the extent that particle sizes of pigments has been controlled for use in polymeric organic coatings and inks. With interest in converting from older printing technologies such as screen and gravure printing to digitally printing on ceramic articles using ink jet nozzle technology, there is also a need to reduce the particle sizes of inorganic metal oxide pigments and to colloidally stabilize the particles of inorganic metal oxides in ink jet inks to avoid settling of the denser mixed metal oxide pigments and plugging of ink jet nozzles.
U.S. Pat. No. 3,778,287 discloses structures of poly 12-hydroxystearic acids (PHS) and polyricinoleic acids (PRA) and their use in aliphatic/aromatic ink/paint systems as dispersants for organic and inorganic pigments.
U.S. Pat. No. 4,645,611 is directed to finely divided particles of magnetic material in an organic liquid containing a dispersant comprising an amine carrying a poly(carbonylalkyleneoxy) chain (PCAO) in which the alkylene groups of the carbonylalkylene contain up to 8 carbon atoms, or an acid-salt thereof. The dispersion is useful for preparing magnetic recording media.
U.S. Pat. No. 4,861,380 is directed to a composition comprising a particulate non-magnetic solid and a dispersant comprising a poly(C2-4-alkyleneimine) carrying at least two mono or poly(carbonyl-C1-7-alkyenoxy) groups in an organic medium.
U.S. Pat. No. 5,700,395 is directed to a dispersant comprising a polyethyleneimine residue carrying polyester chains derived from a caprolactone and at least one other specified lactone or hydroxycarboxylic acid.
U.S. Pat. No. 6,787,600 is directed to a dispersant which comprises a polyamine (e.g., polyallylamine or polyethyleneimine) with two or more different types of polyester chains (e.g., chains from hydroxycarboxylic acids with C1-8-alkylene groups and chains from hydroxycarboxylic acids with C8-30-alkylene).
WO2012/107379A1 is directed to a aminic dispersant with poly(oxyalkylenecarbonyl) solubilizing chain and WO2012/116878A1 is directed to ceramic ink for inkjet printers utilizing a dispersant from polyethyleneimine with homo or copolymers based on lactic acid.
WO2014/146992 is directed to inks for inkjet printers prepared by milling a ceramic inorganic pigment in the presence of a dispersing agent which is the reaction product of polyethyleneimine and a co-polyester of 12-hydroxystearic acid and ε-caprolactone.